Apical extrusion of bacteria when using reciprocating single-file and rotary multifile instrumentation systems

Authors: J. M. Tinoco, G. De-Deus, E. M. B. Tinoco, F. Saavedra, R. A. S. Fidel, L. M. Sassone
Year: 2013
Rubrics: Extrusion
Keywords: disinfection, Extrusion, e.faecalis

Aim To evaluate ex vivo, apical bacterial extrusion associated with two reciprocating single-file systems (WaveOne and Reciproc) compared with a conventional multifile rotary system (BioRace).

Methodology Forty-five human single-rooted mandibular incisors were used. Endodontic access cavities were prepared, and root canals were contaminated with an Enterococcus faecalis suspension. Following incubation at 37 °C for thirty days, the contaminated teeth were divided into three groups of 15 specimens each (G1 – Reciproc, G2 – WaveOne and G3 – BioRace). Positive and negative controls consisted of 5 infected teeth and 3 uninfected incisors that were instrumented with one of the tested NiTi systems, respectively. Bacteria extruded from the apical foramen during instrumentation were collected into vials containing 0.9% NaCl. The microbiological samples were taken from the vials and incubated in brain heart agar medium for 24 h. The resulting bacterial titre, in colony-forming units (CFU) per mL, was determined, and these data were analysed by Wilcoxon matched-pairs signed rank test and Kruskal–Wallis H-test. The level of significance was set at ? = 0.05.

Results No significant difference was found in the number of CFU between the two reciprocating systems (P = 0.41). The conventional multifile rotary system group was associated with significantly higher CFU than both of the two reciprocating groups (P = 0.01).

Conclusions All instrumentation systems extruded bacteria beyond the foramen. However, both reciprocating single-file systems extruded fewer bacteria apically than the conventional multifile rotary system.

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